With the recent explosion of smart mobile devices and location based services, reliable and accurate location sensing has become increasingly important for the operation of a variety of applications, and is now virtually expected by users to be available. However, there are oftentimes circumstances that adversely affect the functionality of location services. For instance, indoors, particularly in commercial office buildings, signal reception from Global Positioning System (GPS) satellites is generally not possible in the absence of line-of-sight signal reception. In addition, there tend to be numerous obstructions in indoor environments that prevent terrestrial location systems from working effectively.
For indoor spaces where GPS does not work, obtaining physical coordinates of locations typically require an end-to-end system that consists of location anchor points (access points) and/or location servers. The deployment of a physical indoor location system is not trivial. In general, mobile devices (e.g., laptops, tablets, wearable devices) without substantial back-end location system support are not capable of obtaining physical locations by themselves.
A practical solution is needed for mobile devices to obtain location information in challenging environments.